Several techniques have been reported for generating music based on input from bio-signals, and for obvious reasons, these methods cannot be applied to non-living objects, such as chemical substances and their mixtures.
Conventional sound source players modify music information, such as measure, rhythm and tempo using the bio-signals, such as pulse rate. Newer music players generate music directly from an Electrocardiogram (ECG) signal by matching amplitudes of the signal to the 88 keys of a piano keyboard.
U.S. Patent Application 20100192754 describes a music generation method based on two types of bio-signals: an ECG or PhotoPlethysmoGraphy (PPG). This method measures heartbeat rate signals of a user and translates heartbeat rate into a note number, heartbeat amplitude of a QRS peak into sound intensity, the difference between two subsequent heartbeat rates into a sound duration, an average heartbeat rate into a time base and measure, and rate/resolution interval increment into a number of bars.
U.S. Pat. No. 6,743,164 discloses a method of transforming micro-variations within a living organism, such as a plant, into an analog electrical signal, and generating a sequence of environmental changes perceptible through the human senses based on the analog signal. The term “micro-variations” includes electrical impedance, dielectric constant, chemical concentrations, electrochemical potential, electrochemical current, mechanical tension, force, pressure, optical transmissivity and reflectivity, chromatic value, magnetic and electrical permeability etc. The sequence of environmental changes can include the generation of music.
Genetic material of all living organisms includes deoxyribonucleic acid (DNA) sequences that consist of four different nucleotides: Adenine, Cytosine, Thymine and Guanine. Much of the DNA in an individual genome encodes twenty amino-acids. U.S. Pat. No. 7,247,782 teaches a method for musically transcribing DNA sequences comprising a) determining a sequence of amino-acids from a sequence of nucleotides, b) determining a sequence of chords in response to the determined amino-acid sequence, c) generating a sequence of tones in response to the nucleotide sequence encoding the amino-acid of each determined chord, and d) generating musical output comprised of the determined chords and tones.
Iannis Xenakis used mathematical models and equations for devising algorithms suitable for composing music [Formalized Music: Thought and Mathematics in Composition; Harmonologia Series, No. 6 (1971) by Iannis Xenakis]. The mathematical equations that were used described abstract systems and subjects such as light and probability distribution.